Currently, in the field of regenerative medicine, studies in which stem cells collected from a subject are caused to proliferate or differentiate ex vivo, and are thereafter transplanted into a subject, thereby promoting regeneration of tissue of the subject, have been carried out. Stem cells are multipotent and can differentiate into a variety of tissues and organs, and they have been attracting attention as cells which are the key to regenerative medicine.
It has been known that in ex vivo cultural proliferation of stem cells, the addition of a serum to the medium is effective. However, when human therapies are targeted, the use of a serum derived from an animal other than humans should be avoided in light of possible safety problems. Therefore, the use of a serum prepared from blood collected from a human, in particular, collected from the same subject is desired. In addition, a culture of stem cells in the field of regenerative medicine requires relatively larger amounts of serum in comparison with blood tests.
As a method of preparing such a serum, a method in which a blood collection tube is used that contains a blood coagulation accelerating solid, such as glass powder, is disclosed (see Patent Document 1). Furthermore, a method of facilitating collection of a serum having a large amount and many kinds of growth factors by bringing the blood into contact with glass powder so as to rapidly separate a coagulation substance such as fibrin mixed in the serum is disclosed (see Patent Document 2). Moreover, a method of producing a serum as a raw material with human plasma is disclosed (see Patent Document 3). In addition, a method of obtaining growth factors by adding a calcium compound and glass beads to plasma is disclosed (see patent document 4).    Patent Document 1: Japanese Unexamined Patent Application Publication No. 2000-000228    Patent Document 2: Japanese Unexamined Patent Application Publication No. Hei 04-83165    Patent Document 3: Japanese Unexamined Patent Application Publication No. 2001-275662    Patent Document 4: Japanese Unexamined Patent Application Publication No. 2004-269409